Abstract

Sturgeon aquaculture is a relatively new but steadily expanding industry. The introduction of sturgeon into intensive aquaculture environments has been accompanied by the recognition of important pathogens. White sturgeon (Acipenser transmontanus) have been cultured since 1979 in the state of California. Significant losses annually have been attributed to viral infections with one of four viruses; an adenovirus (WSAV), two herpesviruses (WSHV type l and 2) and an iridovirus (WSIV). Losses of white sturgeon larvae and fingerlings range from 50% to 95% and may result from infections among fish on commercial farms. Three of the agents (WSAV, WSIV, and WSHV-2) have also been identified in feral stocks of white sturgeon.

Reports of unexplained mortality among young sturgeon on farms in Europe and Russia have been observed. Routine microbiological examinations of these fish have failed to identify parasites or bacteria as the etiological agents (personal communications). Samples from a farm in Northern Europe with fish experiencing episodes of high mortality have yielded microscopic (light and electron) evidence of an iridovirus with properties identical to those of the white sturgeon iridovirus. We will discuss this first identification of an iridovirus infection in Russian sturgeon (Acipenser guldenstadi) or any sturgeon from outside the USA.